The present invention relates to a power steering control system for an industrial truck, more particularly, to an switching circuit for the electric steering motor of the system, which is operated by the accelerator pedal of the truck.
Generally the electric power steering motor is connected to the key switch, and all the time when the key switch is in the condition of ON, the motor continues to drive the hydraulic pump in the power steering system.
In the industrial truck, for example a fork lift truck, the driver often operates the loading mechanism equipped with the truck for a respectable part of the whole operating time. At the time of the loading operation the driver handles some control levers of change over valves, which are hydraulically connecting the cylinders of the loading mechanism and the pump driven by the exclusive electric motor for the hydraulic loading system, but does not operates the steering handle or the accelerator pedal of truck, as the driver is not in need of changing its position.
Therefore the steering motor and the steering pump need not be rotated during the loading operation to save the electric energy of the storage battery and to decrease the noise.